The question of whether **Tylenol (acetaminophen) use during pregnancy can cause autism or later dementia** is complex and currently under active scientific investigation. The available evidence suggests there may be an *association* between prenatal acetaminophen exposure and an increased risk of neurodevelopmental conditions such as autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), but **no definitive causal link has been established**. Regarding dementia, there is no credible evidence connecting acetaminophen use during pregnancy to later dementia in offspring.
### Acetaminophen Use During Pregnancy and Autism Risk
Acetaminophen is widely regarded as the safest over-the-counter medication for pain and fever relief during pregnancy. It is the only analgesic recommended by many health authorities for pregnant women because alternatives like aspirin and ibuprofen carry known risks to the fetus.
In recent years, several large observational studies have reported an *association* between prolonged or frequent acetaminophen use during pregnancy and a higher incidence of neurodevelopmental disorders, including autism and ADHD, in children. For example:
– The **Nurses’ Health Study II** and the **Boston Birth Cohort** found correlations between maternal acetaminophen use and increased risk of autism and ADHD diagnoses in offspring[1].
– These studies suggest the risk may be more pronounced with chronic use throughout pregnancy rather than occasional use.
However, these studies are observational and cannot prove causation. Confounding factors such as the underlying illnesses that prompted acetaminophen use (e.g., infections, inflammation), genetic predispositions, or environmental exposures may also contribute to the observed associations[2].
### Regulatory and Expert Responses
– The **U.S. Food and Drug Administration (FDA)** has acknowledged the accumulating evidence suggesting a possible association between acetaminophen use during pregnancy and neurodevelopmental disorders. In 2025, the FDA initiated a process to update acetaminophen labeling to reflect these concerns and issued a letter to physicians to raise awareness[1][7].
– Despite this, the FDA and the **Centers for Disease Control and Prevention (CDC)** continue to recommend acetaminophen as the safest option for pregnant women needing fever or pain relief, emphasizing that untreated high fever itself poses risks to fetal development[1][2].
– The **American College of Obstetricians and Gynecologists (ACOG)** affirms the safety and benefits of acetaminophen during pregnancy, citing numerous studies supporting its role in maternal well-being without conclusive evidence of harm to the fetus[5].
– The **Society for Maternal-Fetal Medicine (SMFM)** also supports acetaminophen use during pregnancy, advising caution but not discouraging its use based on current evidence[6].
### Scientific Uncertainty and Ongoing Research
Experts like Dr. Zeyan Liew from Yale University emphasize that while associations exist, **no causal relationship has been proven**. He notes that ongoing research aims to clarify whether acetaminophen itself contributes to neurodevelopmental disorders or if other factors explain the link[2].
The complexity arises because autism and ADHD are multifactorial conditions influenced by genetics, environment, and prenatal exposures. Observational studies can detect correlations but cannot isolate acetaminophen as the direct cause without randomized controlled trials, which are ethically impossible in this context.
### Acetaminophen and Dementia Risk
There is **no scientific evidence*
